Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Andromeda Galaxy: 02-18 (44), 02-19 (43), 02-20 (41), 02-21 (39), 02-22 (34) — by astronomy; check the weather when the night is within four days.

2042-02-18astronomy score per night — click a bar for that night2042-03-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-02-18 Tue	44	—	unknown	19:35–21:20 (good, 1.75 h)	89.7° 15:10	10.12	3%	81.7°
2042-02-19 Wed	43	—	unknown	19:35–21:15 (good, 1.67 h)	89.5° 15:10	10.08	0%	69.5°
2042-02-20 Thu	41	—	unknown	19:35–21:15 (good, 1.67 h)	89.7° 15:05	10.04	1%	57.5°
2042-02-21 Fri	39	—	unknown	19:35–21:10 (good, 1.58 h)	89.8° 15:00	9.99	4%	46.7°
2042-02-22 Sat	34	—	unknown	19:40–21:05 (good, 1.42 h)	89.8° 14:55	9.95	10%	38.2°
2042-02-23 Sun	29	—	unknown	19:40–20:50 (good, 1.17 h)	89.6° 14:50	9.91	18%	33.6°
2042-02-24 Mon	23	—	unknown	19:40–20:40 (good, 1.0 h)	89.6° 14:50	9.86	28%	34.4°
2042-02-25 Tue	18	—	unknown	19:40–20:25 (good, 0.75 h)	89.7° 14:45	9.82	39%	39.8°
2042-02-26 Wed	14	—	unknown	19:45–21:20 (marginal, 1.58 h)	89.8° 14:40	9.78	50%	48.0°
2042-02-27 Thu	12	—	unknown	19:45–21:10 (marginal, 1.42 h)	89.7° 14:35	9.73	60%	57.5°
2042-02-28 Fri	11	—	unknown	19:45–21:00 (marginal, 1.25 h)	89.5° 14:30	9.69	70%	67.7°
2042-03-01 Sat	10	—	unknown	19:45–21:00 (marginal, 1.25 h)	89.6° 14:30	9.64	79%	78.0°
2042-03-02 Sun	11	—	unknown	19:45–21:00 (marginal, 1.25 h)	89.8° 14:25	9.6	86%	88.3°
2042-03-03 Mon	12	—	unknown	19:15–21:00 (marginal, 1.75 h)	89.8° 14:20	9.55	92%	98.6°
2042-03-04 Tue	13	—	unknown	19:50–20:00 (good, 0.17 h)	89.7° 14:15	9.5	97%	108.5°
2042-03-05 Wed	14	—	unknown	19:50–20:05 (good, 0.25 h)	89.5° 14:15	9.46	99%	118.1°
2042-03-06 Thu	13	—	unknown	19:50–20:05 (good, 0.25 h)	89.7° 14:10	9.41	100%	127.2°
2042-03-07 Fri	11	—	unknown	19:55–20:05 (good, 0.17 h)	89.8° 14:05	9.36	99%	135.3°
2042-03-08 Sat	12	—	unknown	19:55–20:05 (good, 0.17 h)	89.8° 14:00	9.31	96%	141.8°
2042-03-09 Sun	11	—	unknown	19:55–20:05 (good, 0.17 h)	89.6° 13:55	9.27	92%	146.0°
2042-03-10 Mon	9	—	unknown	19:55–20:00 (good, 0.08 h)	89.6° 13:55	9.22	86%	146.7°
2042-03-11 Tue	7	—	unknown	19:25–20:30 (marginal, 1.08 h)	89.7° 13:50	9.17	78%	143.7°
2042-03-12 Wed	6	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.8° 13:45	9.12	70%	137.8°
2042-03-13 Thu	6	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.7° 13:40	9.07	60%	129.8°
2042-03-14 Fri	5	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.5° 13:35	9.02	50%	120.4°
2042-03-15 Sat	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.6° 13:35	8.97	40%	110.0°
2042-03-16 Sun	3	—	unknown	19:30–19:40 (marginal, 0.17 h)	89.8° 13:30	8.92	30%	98.8°
2042-03-17 Mon	2	—	unknown	19:30–19:35 (marginal, 0.08 h)	89.8° 13:25	8.87	20%	87.1°
2042-03-18 Tue	1	—	unknown	—	89.7° 13:20	8.82	11%	75.1°
2042-03-19 Wed	1	—	unknown	—	89.5° 13:20	8.77	5%	63.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-02-18&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.